Many different filtering devices for cleaning liquid and/or gaseous media or corresponding mixtures, including also high-viscosity and oily media, are known from the state of the art. A particularly problematic aspect of the filtering devices that are known from the state of the art is the removal of the filter cake that becomes deposited on a filter element contained in the device, or mud collected there. On this subject, U.S. Pat. No. 7,055,699 B2 proposes a self cleaning mechanical filter, where a cleaning device is integrated in the filtering device disclosed there and presents suction and washing nozzles that are arranged opposite each other, and where the suction nozzles rest directly against the filter element, and the suction nozzles and the washing nozzles are moved synchronously in the axial and radial direction for removal of the filter cake. The cleaning of the filtering device that is disclosed in U.S. Pat. No. 7,055,699 B2 is very complicated and requires complex control. In addition, because of the movement in both the axial and also the radial direction, a relatively high mechanical driving force needs to be applied, which makes the filtering device disclosed there relatively costly.
Moreover, a filtering device according to the preamble is disclosed in WO 2006/008729, where, for the removal of a filter cake on a filter element in a filtering device, a cleaning head with a nozzle is defined particularly, which rests directly against the filter element, and through which, due to a pressure difference that builds up during the cleaning, the filter cake is sucked off the filter element. For the filtering device that is disclosed there to work properly, it is, however, always necessary to guide the cleaning head of the cleaning device so that it rests directly against the filter element, with the result that the pressure difference that can be generated for cleaning is insufficient in the case of slight unevenness that develops particularly in the filter elements or their surfaces in the case of prolonged use of the filtering device.
The problem of the present invention therefore is to make available a filtering device whose filter material or whose filter element(s) can be cleaned particularly well and simply due to the construction of the device, and which in addition effectively cleans a medium to be cleaned, regardless of whether the latter is gaseous, liquid or a mixture that may be of any type.